Finalmente, la sal seca obtenida en D) se lava con la salmuera reactiva especificada y se procede igual que en B), obteniéndose el producto

The following are general principles for avoiding and minimizing the potential impacts of shoreline stabilization. Most are reflected in the SMP Guidelines. The examples are mostly residential because that is where a majority of new development on eroding shorelines is occurring.

Site planning

Most shorelines are susceptible to erosion, but the need for stabilization can often be avoided through careful development of a site and avoidance of the most hazardous or environmentally sensitive portions.

• Development of shoreline sites should be supported by geological analyses that characterize erosion patterns as well as other hazards such as deep-seated landslides, channel migration, and flooding.

• Identify the key geological and ecological processes influencing a site. Pay special attention to ecologically important features such as riparian vegetation, feeder bluffs, beach habitats, and stream mouths.

Figure 1: This shoreline on southern Whidbey Island was previously protected with a timber bulkhead. Rather than replace it, the owner

reconfigured the bank, planted vegetation, and accepted that a modest level of erosion would continue without jeopardizing upland improvements. (Hugh Shipman photo.)

SMP HANDBOOK

Publication Number: 11-06-010 2 7/15

• Avoid development on unstable shorelines or in areas of rapid erosion where future stabilization measures are likely.

• Beware of activities, such as removing vegetation and altering drainage, which may aggravate existing erosion problems.

• Locate utilities, drainfields, landscaping features, and accessory structures so they can accommodate normal erosion and storm damage or can be readily relocated in the future.

• Consider the long-term

cumulative effect of additional similar development along the same reach of shoreline.

• On marine shorelines, consider the potential for increased erosion and flooding that will accompany higher sea levels.

Managing an eroding shoreline

Where erosion impacts a developed site, carefully assess the need for stabilization and whether there are more effective means of reducing the risk without recourse to conventional erosion control structures.

• Evaluate rates and mechanisms of erosion, and understand its causes, before selecting a stabilization method. Avoid short-term solutions that facilitate development of sites without addressing underlying hazards related to large landslides, channel migration, or sea level rise.

• Address upland contributors of erosion and instability, such as drainage, before building a stabilization structure at the water’s edge.

• Emphasize removal or relocation of at-risk structures wherever possible to reduce their vulnerability and the need for stabilization measures.

• Locate and design other shoreline structures such as docks, stairways, and other improvements so as to accommodate existing site erosion and avoid the need for stabilization.

Figure 2: A number of techniques have been used on this Tacoma shoreline to provide ecological functions, while also managing erosion on a heavily developed waterfront. The bulkhead has been kept landward and wood and marsh vegetation have been installed along the water. (Hugh Shipman photo.)

Publication Number: 11-06-010 3 7/15 Design and construction of erosion control measures

Where stabilization is necessary to protect upland development from imminent threat, the design and construction of erosion control measures should minimize impacts on ecological functions and on geological processes that could adversely impact nearby shorelines.

• Stabilization structures should be located as far landward as possible. Their length should be no longer than necessary to protect the at-risk development.

• Softer erosion control measures should be employed wherever possible. Stabilization should be designed to minimize impacts on shoreline habitats such as beaches and riparian

vegetation.

• Methods should be appropriate for the site, address the underlying causes of erosion, and preserve the ecological functions observed on natural shorelines in the vicinity.

• Complex solutions such as groins, jetties, breakwaters, and channel realignment should only be used where there are significant public benefits, where their effect on a longer reach of shoreline is fully considered, and where adverse impacts can be mitigated.

• Construction of stabilization should minimize unnecessary disturbance to shoreline soils and vegetation, prevent the introduction of contaminants and construction debris, and assure rehabilitation of areas impacted by the work.

Figure 3: Bank stabilization along Hangman Creek in Spokane County includes soil lifts, a rock toe and plants. The project, which was completed in 2014, will reduce erosion and stabilize the stream bank adjacent to U.S. 195. (Mike Maher photo.)

SMP HANDBOOK

Publication Number: 11-06-010 4 7/15

Replacing existing stabilization

Where existing stabilization measures need to be repaired or replaced, there are often

opportunities to restore a more natural, better functioning shoreline, while continuing to address the underlying erosion problem.

• Where possible, locate replacement structures farther landward. Not only does this restore shoreline functions, but it can allow for the use of less expensive stabilization measures.

• Evaluate the need for stabilization in the first place. On some sites,

reconfiguring the proposed

development on the shoreline may make stabilization unnecessary.

• Employ softer stabilization methods such as bioengineering, beach

nourishment and the incorporation of natural vegetation and large wood.

• Remove derelict structures, loose riprap, and construction debris from shoreline.

Sources for Appendix 2

Envirovision and Herrera Environmental, 2007, revised 2010, Protecting Nearshore Habitat and Functions in Puget Sound, Aquatic Habitat Guidelines Working Group, Olympia WA.

http://wdfw.wa.gov/publications/00047/ [1]

Gianou, K., 2014, Soft Shoreline Stabilization: Shoreline Master Program Planning and Implementation Guidance, Shorelands and Environmental Assistance Program, Washington Department of Ecology, Olympia WA, Publication #14-06-009.

https://fortress.wa.gov/ecy/publications/publications/1406009.pdf [3]

Johannessen, J., MacLennan, A., Blue, A., Waggoner, J., Williams, S., Gerstel, W., Barnard, R., Carman, R., and Shipman, H., 2014, Marine Shoreline Design Guidelines, Washington

Department of Fish and Wildlife, Olympia, WA. http://wdfw.wa.gov/publications/01583/ [1]

Figure 4: Replacing this riprap revetment at Twanoh State Park on Hood Canal could include shifting the structure landward, restoring the upper beach, replanting native vegetation, and removing loose riprap. (Hugh Shipman photo.)